Autocrine inhibition of cell motility can drive epithelial branching morphogenesis in the absence of growth

Epithelial branching morphogenesis drives the development of organs such as the lung, salivary gland, kidney and the mammary gland. It involves cell proliferation, cell differentiation and cell migration. An elaborate network of chemical and mechanical signals between the epithelium and the surrounding mesenchymal tissues regulates the formation and growth of branching organs. Surprisingly, when cultured in isolation from mesenchymal tissues, many epithelial tissues retain the ability to exhibit branching morphogenesis even in the absence of proliferation. In this work, we propose a simple, experimentally plausible mechanism that can drive branching morphogenesis in the absence of proliferation and cross-talk with the surrounding mesenchymal tissue. The assumptions of our mathematical model derive from in vitro observations of the behaviour of mammary epithelial cells. These data show that autocrine secretion of the growth factor TGFβ1 inhibits the formation of cell protrusions, leading to curvature-dependent inhibition of sprouting. Our hybrid cellular Potts and partial-differential equation model correctly reproduces the experimentally observed tissue-geometry-dependent determination of the sites of branching, and it suffices for the formation of self-avoiding branching structures in the absence and also in the presence of cell proliferation. This article is part of the theme issue ‘Multi-scale analysis and modelling of collective migration in biological systems’.</p

Design of a Study Assessing Disease Behaviour During the Peri-Diagnostic Period in Patients with Interstitial Lung Disease: The STARLINER Study

Background/Objectives: This study will aim to characterise disease behaviour during the peri-diagnostic period in patients with suspected interstitial lung disease (ILD), including idiopathic pulmonary fibrosis (IPF), using daily home spirometry and accelerometry. Additionally, this study will aim to increase collaboration between secondary and tertiary centres using a digital collaboration platform. Methods: The STARLINER study (NCT03261037) will enrol approximately 180 symptomatic patients aged 50 years or more with radiological evidence of ILD/IPF from community and tertiary centres in Canada and Europe. Approximately two-thirds of sites will be community centres. Patients will be followed during pre-diagnosis (inclusion to diagnosis; up to a maximum of 12 months) and post-diagnosis (diagnosis to treatment initiation; up to a maximum of 6 months). The study will be facilitated by a digital ecosystem consisting of the devices used for home-based assessments and a digital collaboration platform enabling communication between community and tertiary centres, and between clinicians and patients. Planned Outcomes: The primary endpoint will be time-adjusted semi-annual change in forced vital capacity (FVC; in millilitres) during the peri-diagnostic period. Physical functional capacity and patient-reported outcomes (PROs) will also be assessed. FVC and physical functional capacity will be measured using daily home spirometry and accelerometry, and at site visits using spirometry and the 6-min walk test. PROs will be assessed prior to, or during, site visits and will always be completed in the same order. Conclusions: Findings from this study may help to facilitate the early and accurate diagnosis of ILDs by increasing knowledge about disease progression, enabling collaboration between community and tertiary centres and improving communication between clinicians and patients. Trial Registration Number: NCT03261037. Funding: F. Hoffmann-La Roche, Ltd., Basel, Switzerland. Plain Language Summary: Plain language summary available for this article

Flow cytometric immunobead assay for fast and easy detection of PML-RARA fusion proteins for the diagnosis of acute promyelocytic leukemia

The PML-RARA fusion protein is found in approximately 97% of patients with acute promyelocytic leukemia (APL). APL can be associated with life-threatening bleeding complications when undiagnosed and not treated expeditiously. The PML-RARA fusion protein arrests maturation of myeloid cells at the promyelocytic stage, leading to the accumulation of neoplastic promyelocytes. Complete remission can be obtained by treatment with all-trans-retinoic acid (ATRA) in combination with chemotherapy. Diagnosis of APL is based on the detection of t(15;17) by karyotyping, fluorescence in situ hybridization or PCR. These techniques are laborious and demand specialized laboratories. We developed a fast (performed within 4-5 h) and sensitive (detection of at least 10% malignant cells in normal background) flow cytometric immunobead assay for the detection of PML-RARA fusion proteins in cell lysates using a bead-bound anti-RARA capture antibody and a phycoerythrin-conjugated anti-PML detection antibody. Testing of 163 newly diagnosed patients (including 46 APL cases) with the PML-RARA immunobead assay showed full concordance with the PML-RARA PCR results. As the applied antibodies recognize outer domains of the fusion protein, the assay appeared to work independently of the PML gene break point region. Importantly, the assay can be used in parallel with routine immunophenotyping for fast and easy diagnosis of APL

opencobra/cobratoolbox: The COBRA Toolbox 2.0

The COnstraint-Based Reconstruction and Analysis Toolbo

Remodeling of the cardiac sodium channel, connexin 43, and plakoglobin at the intercalated disk in patients with arrhythmogenic cardiomyopathy.

Background Arrhythmogenic cardiomyopathy (AC) is closely associated with desmosomal mutations in a majority of patients. Arrhythmogenesis in patients with AC is likely related to remodeling of cardiac gap junctions and increased levels of fibrosis. Recently, using experimental models, we also identified sodium channel dysfunction secondary to desmosomal dysfunction. Objective To assess the immunoreactive signal levels of the sodium channel protein NaV1.5, as well as connexin43 (Cx43) and plakoglobin (PKG), in myocardial specimens obtained from patients with AC. Methods Left and right ventricular free wall postmortem material was obtained from 5 patients with AC and 5 controls matched for age and sex. Right ventricular septal biopsies were taken from another 15 patients with AC. All patients fulfilled the 2010 revised Task Force Criteria for the diagnosis of AC. Immunohistochemical analyses were performed using antibodies against Cx43, PKG, NaV1.5, plakophilin-2, and N-cadherin. Results N-cadherin and desmoplakin immunoreactive signals and distribution were normal in patients with AC compared to controls. Plakophilin-2 signals were unaffected unless a plakophilin-2 mutation predicting haploinsufficiency was present. Distribution was unchanged compared to that in controls. Immunoreactive signal levels of PKG, Cx43, and NaV1.5 were disturbed in 74%, 70%, and 65% of the patients, respectively. Conclusions A reduced immunoreactive signal of PKG, Cx43, and NaV1.5 at the intercalated disks can be observed in a large majority of the patients. Decreased levels of Nav1.5 might contribute to arrhythmia vulnerability and, in the future, potentially could serve as a new clinically relevant tool for risk assessment strategies